1. Field of the Invention
The present invention relates to a lubricant heating system for use with an internal combustion engine.
2. Description of the Prior Art
It takes a warming-up time of several minutes for an internal combustion engine of an automobile or the like to have its lubricant temperature raised to a sufficient level for its normal operation after it has been started. Moreover, the unevaporated fuel, which may steal into the air-fuel mixture sucked into a combustion chamber during the operation of the engine, may flow down a piston through a clearance, which is formed between the facing ends of a piston ring, during the compression stroke of the piston until it steals into the lubricant below a crankcase. This tendency is increased when the internal combustion engine is run at a cold place or when an alcohol fuel is used. Moreover, the lubricant, which has been mixed with the fuel, has its viscosity lowered to invite a disadvantage that its lubricating performance is degraded.